remove JSONNull

hutool-core/src/main/java/cn/hutool/core/util/ObjUtil.java

@@ -186,15 +186,13 @@ public class ObjUtil {
 	 *
 	 * <pre>
 	 * 1. == null
-	 * 2. equals(null)
 	 * </pre>
 	 *
 	 * @param obj 对象
 	 * @return 是否为null
 	 */
 	public static boolean isNull(final Object obj) {
-		//noinspection ConstantConditions
+		return null == obj;
-		return null == obj || obj.equals(null);
 	}
 
 	/**

hutool-json/src/main/java/cn/hutool/json/InternalJSONUtil.java

@@ -59,8 +59,8 @@ public final class InternalJSONUtil {
 	 * @throws JSONException If the value is or contains an invalid number.
 	 */
 	static String valueToString(final Object value) throws JSONException {
-		if (value == null || value instanceof JSONNull) {
+		if (value == null) {
-			return JSONNull.NULL.toString();
+			return StrUtil.NULL;
 		}
 		if (value instanceof JSONString) {
 			try {
@@ -94,7 +94,7 @@ public final class InternalJSONUtil {
 	public static Object stringToValue(final String string) {
 		// null处理
 		if (StrUtil.isEmpty(string) || StrUtil.NULL.equalsIgnoreCase(string)) {
-			return JSONNull.NULL;
+			return null;
 		}
 
 		// boolean处理

hutool-json/src/main/java/cn/hutool/json/JSON.java

@@ -36,7 +36,9 @@ public interface JSON extends Cloneable, Serializable {
 	 * @see BeanPath#get(Object)
 	 * @since 4.0.6
 	 */
-	Object getByPath(String expression);
+	default Object getByPath(String expression){
+		return BeanPath.of(expression).get(this);
+	}
 
 	/**
 	 * 设置表达式指定位置（或filed对应）的值<br>
@@ -59,7 +61,9 @@ public interface JSON extends Cloneable, Serializable {
 	 * @param expression 表达式
 	 * @param value      值
 	 */
-	void putByPath(String expression, Object value);
+	default void putByPath(String expression, Object value){
+		BeanPath.of(expression).set(this, value);
+	}
 
 	/**
 	 * 通过表达式获取JSON中嵌套的对象<br>

hutool-json/src/main/java/cn/hutool/json/JSONArray.java

@@ -1,13 +1,12 @@
 package cn.hutool.json;
 
-import cn.hutool.core.bean.BeanPath;
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.convert.Convert;
 import cn.hutool.core.convert.impl.ArrayConverter;
 import cn.hutool.core.lang.func.Filter;
 import cn.hutool.core.lang.mutable.Mutable;
-import cn.hutool.core.lang.mutable.MutableObj;
 import cn.hutool.core.lang.mutable.MutableEntry;
+import cn.hutool.core.lang.mutable.MutableObj;
 import cn.hutool.core.text.StrJoiner;
 import cn.hutool.core.util.ObjUtil;
 import cn.hutool.json.serialize.JSONWriter;
@@ -192,19 +191,9 @@ public class JSONArray implements JSON, JSONGetter<Integer>, List<Object>, Rando
 		return (index < 0 || index >= this.size()) ? defaultValue : this.rawList.get(index);
 	}
 
-	@Override
-	public Object getByPath(final String expression) {
-		return BeanPath.of(expression).get(this);
-	}
-
 	@Override
 	public <T> T getByPath(final String expression, final Class<T> resultType) {
-		return JSONConverter.jsonConvert(resultType, getByPath(expression), true);
+		return JSONConverter.jsonConvert(resultType, getByPath(expression), this.config.isIgnoreError());
-	}
-
-	@Override
-	public void putByPath(final String expression, final Object value) {
-		BeanPath.of(expression).set(this, value);
 	}
 
 	/**
@@ -376,6 +365,9 @@ public class JSONArray implements JSON, JSONGetter<Integer>, List<Object>, Rando
 		}
 		final ArrayList<Object> list = new ArrayList<>(c.size());
 		for (final Object object : c) {
+			if(null == object && config.isIgnoreNullValue()){
+				continue;
+			}
 			list.add(JSONUtil.wrap(object, this.config));
 		}
 		return rawList.addAll(index, list);
@@ -428,25 +420,36 @@ public class JSONArray implements JSON, JSONGetter<Integer>, List<Object>, Rando
 			}
 		}
 
+		// 越界则追加到指定位置
 		if (index >= size()) {
 			add(index, element);
+			return null;
+		}
+		if(null == element && config.isIgnoreNullValue()){
+			return null;
 		}
 		return this.rawList.set(index, JSONUtil.wrap(element, this.config));
 	}
 
 	@Override
-	public void add(final int index, final Object element) {
+	public void add(int index, final Object element) {
-		if (index < 0) {
+		if(null == element && config.isIgnoreNullValue()){
-			throw new JSONException("JSONArray[{}] not found.", index);
+			return;
 		}
 		if (index < this.size()) {
+			if (index < 0) {
+				index = 0;
+			}
 			InternalJSONUtil.testValidity(element);
 			this.rawList.add(index, JSONUtil.wrap(element, this.config));
 		} else {
-			while (index != this.size()) {
+			if(false == config.isIgnoreNullValue()){
-				this.add(JSONNull.NULL);
+				while (index != this.size()) {
+					// 非末尾，则填充null
+					this.add(null);
+				}
 			}
-			this.set(element);
+			this.add(element);
 		}
 
 	}
@@ -583,6 +586,10 @@ public class JSONArray implements JSON, JSONGetter<Integer>, List<Object>, Rando
 				return false;
 			}
 		}
+		if(null == obj && config.isIgnoreNullValue()){
+			// 忽略空则不添加
+			return false;
+		}
 		return this.rawList.add(obj);
 	}
 }

hutool-json/src/main/java/cn/hutool/json/JSONConverter.java

@@ -53,7 +53,7 @@ public class JSONConverter implements Converter {
 	 */
 	@SuppressWarnings("unchecked")
 	protected static <T> T jsonConvert(final Type targetType, final Object value, final boolean ignoreError) throws ConvertException {
-		if (JSONUtil.isNull(value)) {
+		if (null == value) {
 			return null;
 		}
 
@@ -91,7 +91,7 @@ public class JSONConverter implements Converter {
 	 */
 	@SuppressWarnings("unchecked")
 	protected static <T> T jsonToBean(final Type targetType, final Object value, final boolean ignoreError) throws ConvertException {
-		if (JSONUtil.isNull(value)) {
+		if (null == value) {
 			return null;
 		}
 

hutool-json/src/main/java/cn/hutool/json/JSONGetter.java

@@ -6,6 +6,7 @@ import cn.hutool.core.date.DateUtil;
 import cn.hutool.core.date.LocalDateTimeUtil;
 import cn.hutool.core.lang.getter.OptNullBasicTypeFromObjectGetter;
 import cn.hutool.core.text.StrUtil;
+import cn.hutool.core.util.ObjUtil;
 
 import java.time.LocalDateTime;
 import java.util.Date;
@@ -32,10 +33,10 @@ public interface JSONGetter<K> extends OptNullBasicTypeFromObjectGetter<K> {
 	 * key对应值是否为{@code null}或无此key
 	 *
 	 * @param key 键
-	 * @return true 无此key或值为{@code null}或{@link JSONNull#NULL}返回{@code false}，其它返回{@code true}
+	 * @return true 无此key或值为{@code null}返回{@code false}，其它返回{@code true}
 	 */
 	default boolean isNull(final K key) {
-		return JSONUtil.isNull(this.getObj(key));
+		return ObjUtil.isNull(this.getObj(key));
 	}
 
 	/**
@@ -70,7 +71,7 @@ public interface JSONGetter<K> extends OptNullBasicTypeFromObjectGetter<K> {
 	 */
 	default JSONArray getJSONArray(final K key) {
 		final Object object = this.getObj(key);
-		if (JSONUtil.isNull(object)) {
+		if (ObjUtil.isNull(object)) {
 			return null;
 		}
 
@@ -89,7 +90,7 @@ public interface JSONGetter<K> extends OptNullBasicTypeFromObjectGetter<K> {
 	 */
 	default JSONObject getJSONObject(final K key) {
 		final Object object = this.getObj(key);
-		if (JSONUtil.isNull(object)) {
+		if (ObjUtil.isNull(object)) {
 			return null;
 		}
 
@@ -133,7 +134,7 @@ public interface JSONGetter<K> extends OptNullBasicTypeFromObjectGetter<K> {
 	default Date getDate(final K key, final Date defaultValue) {
 		// 默认转换
 		final Object obj = getObj(key);
-		if (JSONUtil.isNull(obj)) {
+		if (ObjUtil.isNull(obj)) {
 			return defaultValue;
 		}
 		if (obj instanceof Date) {
@@ -167,7 +168,7 @@ public interface JSONGetter<K> extends OptNullBasicTypeFromObjectGetter<K> {
 	default LocalDateTime getLocalDateTime(final K key, final LocalDateTime defaultValue) {
 		// 默认转换
 		final Object obj = getObj(key);
-		if (JSONUtil.isNull(obj)) {
+		if (ObjUtil.isNull(obj)) {
 			return defaultValue;
 		}
 		if (obj instanceof LocalDateTime) {
@@ -228,7 +229,7 @@ public interface JSONGetter<K> extends OptNullBasicTypeFromObjectGetter<K> {
 	 */
 	default <T> T get(final K key, final Class<T> type, final boolean ignoreError) throws ConvertException {
 		final Object value = this.getObj(key);
-		if (JSONUtil.isNull(value)) {
+		if (ObjUtil.isNull(value)) {
 			return null;
 		}
 		return JSONConverter.jsonConvert(type, value, ignoreError);

hutool-json/src/main/java/cn/hutool/json/JSONNull.java

@@ -1,46 +0,0 @@
-package cn.hutool.json;
-
-import cn.hutool.core.text.StrUtil;
-
-import java.io.Serializable;
-
-/**
- * 用于定义{@code null}，与Javascript中null相对应<br>
- * Java中的{@code null}值在js中表示为undefined。
- *
- * @author Looly
- */
-public class JSONNull implements Serializable {
-	private static final long serialVersionUID = 2633815155870764938L;
-
-	/**
-	 * {@code NULL} 对象用于减少歧义来表示Java 中的{@code null} <br>
-	 * {@code NULL.equals(null)} 返回 {@code true}. <br>
-	 * {@code NULL.toString()} 返回 {@code "null"}.
-	 */
-	public static final JSONNull NULL = new JSONNull();
-
-	/**
-	 * A Null object is equal to the null value and to itself.
-	 * 对象与其本身和{@code null}值相等
-	 *
-	 * @param object An object to test for nullness.
-	 * @return true if the object parameter is the JSONObject.NULL object or null.
-	 */
-	@SuppressWarnings("EqualsWhichDoesntCheckParameterClass")
-	@Override
-	public boolean equals(final Object object) {
-		return object == null || (object == this);
-	}
-
-	/**
-	 * Get the "null" string value.
-	 * 获得“null”字符串
-	 *
-	 * @return The string "null".
-	 */
-	@Override
-	public String toString() {
-		return StrUtil.NULL;
-	}
-}

hutool-json/src/main/java/cn/hutool/json/JSONObject.java

@@ -1,6 +1,5 @@
 package cn.hutool.json;
 
-import cn.hutool.core.bean.BeanPath;
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.lang.func.Filter;
 import cn.hutool.core.lang.mutable.MutableEntry;
@@ -182,19 +181,9 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 		return this.getOrDefault(key, defaultValue);
 	}
 
-	@Override
-	public Object getByPath(final String expression) {
-		return BeanPath.of(expression).get(this);
-	}
-
 	@Override
 	public <T> T getByPath(final String expression, final Class<T> resultType) {
-		return JSONConverter.jsonConvert(resultType, getByPath(expression), true);
+		return JSONConverter.jsonConvert(resultType, getByPath(expression), this.config.isIgnoreError());
-	}
-
-	@Override
-	public void putByPath(final String expression, final Object value) {
-		BeanPath.of(expression).set(this, value);
 	}
 
 	/**
@@ -219,7 +208,23 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 	 * @throws JSONException 值是无穷数字抛出此异常
 	 */
 	public JSONObject set(final String key, final Object value) throws JSONException {
-		return set(key, value, null, false);
+		put(key, value, null, false);
+		return this;
+	}
+
+	/**
+	 * 一次性Put 键值对，如果key已经存在抛出异常，如果键值中有null值，忽略
+	 *
+	 * @param key    键
+	 * @param value  值对象，可以是以下类型: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONNull.NULL.
+	 * @param filter 键值对过滤编辑器，可以通过实现此接口，完成解析前对键值对的过滤和修改操作，{@code null}表示不过滤
+	 * @return this
+	 * @throws JSONException 值是无穷数字、键重复抛出异常
+	 * @since 5.8.0
+	 */
+	public JSONObject setOnce(final String key, final Object value, final Filter<MutableEntry<String, Object>> filter) throws JSONException {
+		put(key, value, filter, true);
+		return this;
 	}
 
 	/**
@@ -238,32 +243,6 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 		return this;
 	}
 
-	/**
-	 * 一次性Put 键值对，如果key已经存在抛出异常，如果键值中有null值，忽略
-	 *
-	 * @param key   键
-	 * @param value 值对象，可以是以下类型: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONNull.NULL.
-	 * @return this.
-	 * @throws JSONException 值是无穷数字、键重复抛出异常
-	 */
-	public JSONObject putOnce(final String key, final Object value) throws JSONException {
-		return setOnce(key, value, null);
-	}
-
-	/**
-	 * 一次性Put 键值对，如果key已经存在抛出异常，如果键值中有null值，忽略
-	 *
-	 * @param key    键
-	 * @param value  值对象，可以是以下类型: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONNull.NULL.
-	 * @param filter 键值对过滤编辑器，可以通过实现此接口，完成解析前对键值对的过滤和修改操作，{@code null}表示不过滤
-	 * @return this
-	 * @throws JSONException 值是无穷数字、键重复抛出异常
-	 * @since 5.8.0
-	 */
-	public JSONObject setOnce(final String key, final Object value, final Filter<MutableEntry<String, Object>> filter) throws JSONException {
-		return set(key, value, filter, true);
-	}
-
 	/**
 	 * 在键和值都为非空的情况下put到JSONObject中
 	 *
@@ -272,7 +251,7 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 	 * @return this.
 	 * @throws JSONException 值是无穷数字
 	 */
-	public JSONObject putOpt(final String key, final Object value) throws JSONException {
+	public JSONObject setOpt(final String key, final Object value) throws JSONException {
 		if (key != null && value != null) {
 			this.set(key, value);
 		}
@@ -287,29 +266,12 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 	}
 
 	/**
-	 * 积累值。类似于set，当key对应value已经存在时，与value组成新的JSONArray. <br>
+	 * 追加值.
-	 * 如果只有一个值，此值就是value，如果多个值，则是添加到新的JSONArray中
+	 * <ul>
-	 *
+	 *     <li>如果键值对不存在或对应值为{@code null}，则value为单独值</li>
-	 * @param key   键
+	 *     <li>如果值是一个{@link JSONArray}，追加之</li>
-	 * @param value 被积累的值
+	 *     <li>如果值是一个其他值，则和旧值共同组合为一个{@link JSONArray}</li>
-	 * @return this.
+	 * </ul>
-	 * @throws JSONException 如果给定键为{@code null}或者键对应的值存在且为非JSONArray
-	 */
-	public JSONObject accumulate(final String key, final Object value) throws JSONException {
-		InternalJSONUtil.testValidity(value);
-		final Object object = this.getObj(key);
-		if (object == null) {
-			this.set(key, value);
-		} else if (object instanceof JSONArray) {
-			((JSONArray) object).set(value);
-		} else {
-			this.set(key, JSONUtil.createArray(this.config).set(object).set(value));
-		}
-		return this;
-	}
-
-	/**
-	 * 追加值，如果key无对应值，就添加一个JSONArray，其元素只有value，如果值已经是一个JSONArray，则添加到值JSONArray中。
 	 *
 	 * @param key   键
 	 * @param value 值
@@ -320,11 +282,11 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 		InternalJSONUtil.testValidity(value);
 		final Object object = this.getObj(key);
 		if (object == null) {
-			this.set(key, new JSONArray(this.config).set(value));
+			this.set(key, value);
 		} else if (object instanceof JSONArray) {
-			this.set(key, ((JSONArray) object).set(value));
+			((JSONArray) object).set(value);
 		} else {
-			throw new JSONException("JSONObject [" + key + "] is not a JSONArray.");
+			this.set(key, JSONUtil.createArray(this.config).set(object).set(value));
 		}
 		return this;
 	}
@@ -435,13 +397,13 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 	 * @param value          值对象. 可以是以下类型: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONNull.NULL.
 	 * @param filter         键值对过滤编辑器，可以通过实现此接口，完成解析前对键值对的过滤和修改操作，{@code null}表示不过滤
 	 * @param checkDuplicate 是否检查重复键，如果为{@code true}，则出现重复键时抛出{@link JSONException}异常
-	 * @return this.
+	 * @return 旧值
 	 * @throws JSONException 值是无穷数字抛出此异常
 	 * @since 5.8.0
 	 */
 	private Object put(String key, Object value, final Filter<MutableEntry<String, Object>> filter, final boolean checkDuplicate) throws JSONException {
 		if (null == key) {
-			return this;
+			return null;
 		}
 
 		// 添加前置过滤，通过MutablePair实现过滤、修改键值对等
@@ -453,12 +415,12 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 				value = pair.getValue();
 			} else {
 				// 键值对被过滤
-				return this;
+				return null;
 			}
 		}
 
 		final boolean ignoreNullValue = this.config.isIgnoreNullValue();
-		if (ObjUtil.isNull(value) && ignoreNullValue) {
+		if (null == value && ignoreNullValue) {
 			// 忽略值模式下如果值为空清除key
 			return this.remove(key);
 		} else if (checkDuplicate && containsKey(key)) {

hutool-json/src/main/java/cn/hutool/json/JSONParser.java

@@ -106,7 +106,7 @@ public class JSONParser {
 			for (; ; ) {
 				if (x.nextClean() == ',') {
 					x.back();
-					jsonArray.addRaw(JSONNull.NULL, filter);
+					jsonArray.addRaw(null, filter);
 				} else {
 					x.back();
 					jsonArray.addRaw(x.nextValue(), filter);

hutool-json/src/main/java/cn/hutool/json/JSONTokener.java

@@ -411,7 +411,7 @@ public class JSONTokener {
 			while (true) {
 				if (this.nextClean() == ',') {
 					this.back();
-					jsonArray.add(JSONNull.NULL);
+					jsonArray.add(null);
 				} else {
 					this.back();
 					jsonArray.add(this.nextValue());

hutool-json/src/main/java/cn/hutool/json/JSONUtil.java

@@ -716,7 +716,7 @@ public class JSONUtil {
 	@SuppressWarnings({"rawtypes", "unchecked"})
 	public static Object wrap(final Object object, final JSONConfig jsonConfig) {
 		if (object == null) {
-			return jsonConfig.isIgnoreNullValue() ? null : JSONNull.NULL;
+			return null;
 		}
 		if (object instanceof JSON //
 				|| ObjUtil.isNull(object) //
@@ -836,22 +836,6 @@ public class JSONUtil {
 		return StrUtil.isWrap(StrUtil.trim(str), '[', ']');
 	}
 
-	/**
-	 * 是否为null对象，null的情况包括：
-	 *
-	 * <pre>
-	 * 1. {@code null}
-	 * 2. {@link JSONNull}
-	 * </pre>
-	 *
-	 * @param obj 对象
-	 * @return 是否为null
-	 * @since 4.5.7
-	 */
-	public static boolean isNull(final Object obj) {
-		return null == obj || obj instanceof JSONNull;
-	}
-
 	/**
 	 * XML转JSONObject<br>
 	 * 转换过程中一些信息可能会丢失，JSON中无法区分节点和属性，相同的节点将被处理为JSONArray。

hutool-json/src/main/java/cn/hutool/json/serialize/JSONWriter.java

@@ -14,7 +14,6 @@ import cn.hutool.json.JSON;
 import cn.hutool.json.JSONArray;
 import cn.hutool.json.JSONConfig;
 import cn.hutool.json.JSONException;
-import cn.hutool.json.JSONNull;
 import cn.hutool.json.JSONObject;
 import cn.hutool.json.JSONString;
 import cn.hutool.json.JSONUtil;
@@ -96,6 +95,7 @@ public class JSONWriter extends Writer {
 	 * @return this
 	 */
 	public JSONWriter beginObj() {
+		//noinspection resource
 		writeRaw(CharUtil.DELIM_START);
 		return this;
 	}
@@ -106,6 +106,7 @@ public class JSONWriter extends Writer {
 	 * @return this
 	 */
 	public JSONWriter beginArray() {
+		//noinspection resource
 		writeRaw(CharUtil.BRACKET_START);
 		arrayMode = true;
 		return this;
@@ -118,7 +119,9 @@ public class JSONWriter extends Writer {
 	 */
 	public JSONWriter end() {
 		// 换行缩进
+		//noinspection resource
 		writeLF().writeSpace(indent);
+		//noinspection resource
 		writeRaw(arrayMode ? CharUtil.BRACKET_END : CharUtil.DELIM_END);
 		flush();
 		arrayMode = false;
@@ -135,22 +138,24 @@ public class JSONWriter extends Writer {
 	 */
 	public JSONWriter writeKey(final String key) {
 		if (needSeparator) {
+			//noinspection resource
 			writeRaw(CharUtil.COMMA);
 		}
 		// 换行缩进
+		//noinspection resource
 		writeLF().writeSpace(indentFactor + indent);
 		return writeRaw(JSONUtil.quote(key));
 	}
 
 	/**
 	 * 写出值，自动处理分隔符和缩进，自动判断类型，并根据不同类型写出特定格式的值<br>
-	 * 如果写出的值为{@code null}或者{@link JSONNull}，且配置忽略null，则跳过。
+	 * 如果写出的值为{@code null}，且配置忽略null，则跳过。
 	 *
 	 * @param value 值
 	 * @return this
 	 */
 	public JSONWriter writeValue(final Object value) {
-		if(JSONUtil.isNull(value) && config.isIgnoreNullValue()){
+		if (null == value && config.isIgnoreNullValue()) {
 			return this;
 		}
 		return writeValueDirect(value);
@@ -159,16 +164,17 @@ public class JSONWriter extends Writer {
 	/**
 	 * 写出字段名及字段值，如果字段值是{@code null}且忽略null值，则不写出任何内容
 	 *
-	 * @param key 字段名
+	 * @param key   字段名
 	 * @param value 字段值
 	 * @return this
 	 * @since 5.7.6
 	 */
-	public JSONWriter writeField(final String key, final Object value){
+	public JSONWriter writeField(final String key, final Object value) {
-		if(JSONUtil.isNull(value) && config.isIgnoreNullValue()){
+		if (null == value && config.isIgnoreNullValue()) {
 			return this;
 		}
 
+		//noinspection resource
 		return writeKey(key).writeValueDirect(value);
 	}
 
@@ -192,6 +198,7 @@ public class JSONWriter extends Writer {
 	}
 
 	// ------------------------------------------------------------------------------ Private methods
+
 	/**
 	 * 写出值，自动处理分隔符和缩进，自动判断类型，并根据不同类型写出特定格式的值
 	 *
@@ -201,11 +208,14 @@ public class JSONWriter extends Writer {
 	private JSONWriter writeValueDirect(final Object value) {
 		if (arrayMode) {
 			if (needSeparator) {
+				//noinspection resource
 				writeRaw(CharUtil.COMMA);
 			}
 			// 换行缩进
+			//noinspection resource
 			writeLF().writeSpace(indentFactor + indent);
 		} else {
+			//noinspection resource
 			writeRaw(CharUtil.COLON).writeSpace(1);
 		}
 		needSeparator = true;
@@ -220,24 +230,26 @@ public class JSONWriter extends Writer {
 	 */
 	private JSONWriter writeObjValue(final Object value) {
 		final int indent = indentFactor + this.indent;
-		if (value == null || value instanceof JSONNull) {
+		if (value == null) {
-			writeRaw(JSONNull.NULL.toString());
+			//noinspection resource
+			writeRaw(StrUtil.NULL);
 		} else if (value instanceof JSON) {
 			((JSON) value).write(writer, indentFactor, indent);
 		} else if (value instanceof Map || value instanceof Map.Entry) {
 			new JSONObject(value).write(writer, indentFactor, indent);
 		} else if (value instanceof Iterable || value instanceof Iterator || ArrayUtil.isArray(value)) {
-			if(value instanceof byte[]){
+			if (value instanceof byte[]) {
 				// issue#I59LW4
 				// json内容中的bytes默认转为Base64
 				writeStrValue(Base64.encode((byte[]) value));
-			}else{
+			} else {
 				new JSONArray(value).write(writer, indentFactor, indent);
 			}
 		} else if (value instanceof Number) {
 			writeNumberValue((Number) value);
 		} else if (value instanceof Date || value instanceof Calendar || value instanceof TemporalAccessor) {
 			final String format = (null == config) ? null : config.getDateFormat();
+			//noinspection resource
 			writeRaw(formatDate(value, format));
 		} else if (value instanceof Boolean) {
 			writeBooleanValue((Boolean) value);
@@ -260,6 +272,7 @@ public class JSONWriter extends Writer {
 	private void writeNumberValue(final Number number) {
 		// since 5.6.2可配置是否去除末尾多余0，例如如果为true,5.0返回5
 		final boolean isStripTrailingZeros = null == config || config.isStripTrailingZeros();
+		//noinspection resource
 		writeRaw(NumberUtil.toStr(number, isStripTrailingZeros));
 	}
 
@@ -269,6 +282,7 @@ public class JSONWriter extends Writer {
 	 * @param value Boolean值
 	 */
 	private void writeBooleanValue(final Boolean value) {
+		//noinspection resource
 		writeRaw(value.toString());
 	}
 
@@ -287,6 +301,7 @@ public class JSONWriter extends Writer {
 			throw new JSONException(e);
 		}
 		if (null != valueStr) {
+			//noinspection resource
 			writeRaw(valueStr);
 		} else {
 			writeStrValue(jsonString.toString());
@@ -317,6 +332,7 @@ public class JSONWriter extends Writer {
 	private void writeSpace(final int count) {
 		if (indentFactor > 0) {
 			for (int i = 0; i < count; i++) {
+				//noinspection resource
 				writeRaw(CharUtil.SPACE);
 			}
 		}
@@ -329,6 +345,7 @@ public class JSONWriter extends Writer {
 	 */
 	private JSONWriter writeLF() {
 		if (indentFactor > 0) {
+			//noinspection resource
 			writeRaw(CharUtil.LF);
 		}
 		return this;

hutool-json/src/main/java/cn/hutool/json/xml/JSONXMLParser.java

@@ -1,5 +1,6 @@
 package cn.hutool.json.xml;
 
+import cn.hutool.core.text.StrUtil;
 import cn.hutool.json.InternalJSONUtil;
 import cn.hutool.json.JSONException;
 import cn.hutool.json.JSONObject;
@@ -63,7 +64,7 @@ public class JSONXMLParser {
 					if (x.next() == '[') {
 						string = x.nextCDATA();
 						if (string.length() > 0) {
-							context.accumulate("content", string);
+							context.append("content", string);
 						}
 						return false;
 					}
@@ -126,10 +127,10 @@ public class JSONXMLParser {
 						if (!(token instanceof String)) {
 							throw x.syntaxError("Missing value");
 						}
-						jsonobject.accumulate(string, keepStrings ? token : InternalJSONUtil.stringToValue((String) token));
+						jsonobject.append(string, keepStrings ? token : InternalJSONUtil.stringToValue((String) token));
 						token = null;
 					} else {
-						jsonobject.accumulate(string, "");
+						jsonobject.append(string, "");
 					}
 
 				} else if (token == XML.SLASH) {
@@ -138,9 +139,9 @@ public class JSONXMLParser {
 						throw x.syntaxError("Misshaped tag");
 					}
 					if (jsonobject.size() > 0) {
-						context.accumulate(tagName, jsonobject);
+						context.append(tagName, jsonobject);
 					} else {
-						context.accumulate(tagName, "");
+						context.append(tagName, StrUtil.EMPTY);
 					}
 					return false;
 
@@ -156,18 +157,18 @@ public class JSONXMLParser {
 						} else if (token instanceof String) {
 							string = (String) token;
 							if (string.length() > 0) {
-								jsonobject.accumulate("content", keepStrings ? token : InternalJSONUtil.stringToValue(string));
+								jsonobject.append("content", keepStrings ? token : InternalJSONUtil.stringToValue(string));
 							}
 
 						} else if (token == XML.LT) {
 							// Nested element
 							if (parse(x, jsonobject, tagName, keepStrings)) {
 								if (jsonobject.size() == 0) {
-									context.accumulate(tagName, "");
+									context.append(tagName, "");
 								} else if (jsonobject.size() == 1 && jsonobject.get("content") != null) {
-									context.accumulate(tagName, jsonobject.get("content"));
+									context.append(tagName, jsonobject.get("content"));
 								} else {
-									context.accumulate(tagName, jsonobject);
+									context.append(tagName, jsonobject);
 								}
 								return false;
 							}

hutool-json/src/test/java/cn/hutool/json/JSONArrayTest.java

@@ -166,7 +166,7 @@ public class JSONArrayTest {
 	@Test
 	public void toListWithNullTest() {
 		final String json = "[null,{'akey':'avalue','bkey':'bvalue'}]";
-		final JSONArray ja = JSONUtil.parseArray(json);
+		final JSONArray ja = JSONUtil.parseArray(json, JSONConfig.of().setIgnoreNullValue(false));
 
 		final List<KeyBean> list = ja.toList(KeyBean.class);
 		Assert.assertNull(list.get(0));
@@ -218,8 +218,13 @@ public class JSONArrayTest {
 
 	@Test
 	public void putToIndexTest(){
-		final JSONArray jsonArray = new JSONArray();
+		JSONArray jsonArray = new JSONArray();
-		jsonArray.put(3, "test");
+		jsonArray.set(3, "test");
+		// 默认忽略null值，因此空位无值，只有一个值
+		Assert.assertEquals(1, jsonArray.size());
+
+		jsonArray = new JSONArray(JSONConfig.of().setIgnoreNullValue(false));
+		jsonArray.set(3, "test");
 		// 第三个位置插入值，0~2都是null
 		Assert.assertEquals(4, jsonArray.size());
 	}

hutool-json/src/test/java/cn/hutool/json/JSONNullTest.java

@@ -12,9 +12,9 @@ public class JSONNullTest {
 				"            \"device_status_date\": null,\n" +
 				"            \"imsi\": null,\n" +
 				"            \"act_date\": \"2021-07-23T06:23:26.000+00:00\"}");
-		Assert.assertEquals(JSONNull.class, bodyjson.get("device_model").getClass());
+		Assert.assertNull(bodyjson.get("device_model"));
-		Assert.assertEquals(JSONNull.class, bodyjson.get("device_status_date").getClass());
+		Assert.assertNull(bodyjson.get("device_status_date"));
-		Assert.assertEquals(JSONNull.class, bodyjson.get("imsi").getClass());
+		Assert.assertNull(bodyjson.get("imsi"));
 
 		bodyjson.getConfig().setIgnoreNullValue(true);
 		Assert.assertEquals("{\"act_date\":\"2021-07-23T06:23:26.000+00:00\"}", bodyjson.toString());
@@ -31,4 +31,26 @@ public class JSONNullTest {
 		Assert.assertFalse(bodyjson.containsKey("device_status_date"));
 		Assert.assertFalse(bodyjson.containsKey("imsi"));
 	}
+
+	@Test
+	public void setNullTest(){
+		// 忽略null
+		String json1 = JSONUtil.createObj().set("key1", null).toString();
+		Assert.assertEquals("{}", json1);
+
+		// 不忽略null
+		json1 = JSONUtil.createObj(JSONConfig.of().setIgnoreNullValue(false)).set("key1", null).toString();
+		Assert.assertEquals("{\"key1\":null}", json1);
+	}
+
+	@Test
+	public void setNullOfJSONArrayTest(){
+		// 忽略null
+		String json1 = JSONUtil.createArray().set(null).toString();
+		Assert.assertEquals("[]", json1);
+
+		// 不忽略null
+		json1 = JSONUtil.createArray(JSONConfig.of().setIgnoreNullValue(false)).set(null).toString();
+		Assert.assertEquals("[null]", json1);
+	}
 }

hutool-json/src/test/java/cn/hutool/json/JSONObjectTest.java

@@ -116,7 +116,7 @@ public class JSONObjectTest {
 		Assert.assertEquals(jsonObject.get("d"), true);
 
 		Assert.assertTrue(jsonObject.containsKey("e"));
-		Assert.assertEquals(jsonObject.get("e"), JSONNull.NULL);
+		Assert.assertNull(jsonObject.get("e"));
 	}
 
 	@Test
@@ -460,7 +460,7 @@ public class JSONObjectTest {
 		json.append("date", DateUtil.parse("2020-06-05 11:16:11"));
 		json.append("bbb", "222");
 		json.append("aaa", "123");
-		Assert.assertEquals("{\"date\":[\"2020-06-05 11:16:11\"],\"bbb\":[\"222\"],\"aaa\":[\"123\"]}", json.toString());
+		Assert.assertEquals("{\"date\":\"2020-06-05 11:16:11\",\"bbb\":\"222\",\"aaa\":\"123\"}", json.toString());
 	}
 
 	@Test
@@ -612,14 +612,14 @@ public class JSONObjectTest {
 	}
 
 	@Test
-	public void accumulateTest() {
+	public void appendTest() {
-		final JSONObject jsonObject = JSONUtil.createObj().accumulate("key1", "value1");
+		final JSONObject jsonObject = JSONUtil.createObj().append("key1", "value1");
 		Assert.assertEquals("{\"key1\":\"value1\"}", jsonObject.toString());
 
-		jsonObject.accumulate("key1", "value2");
+		jsonObject.append("key1", "value2");
 		Assert.assertEquals("{\"key1\":[\"value1\",\"value2\"]}", jsonObject.toString());
 
-		jsonObject.accumulate("key1", "value3");
+		jsonObject.append("key1", "value3");
 		Assert.assertEquals("{\"key1\":[\"value1\",\"value2\",\"value3\"]}", jsonObject.toString());
 	}